1. 山口：美国莫利矿业公司(Molycorp Minerals)准备开采已经荒废将近20年的加州山口(Mountain Pass)稀土矿,加拿大阿弗龙(Avalon)稀有金属公司正试图在加拿大西北部开发新矿,澳大利亚Lynas稀土公司和阿拉弗拉(Arafura)资源有限公司也准备继续开发稀土矿藏,

2. 隘口：赶紧再上网查查可能经过的两个隘口(Mountain Pass)的情况,2号公路路程较近,但经过的Stevens Pass海拔1238米,气温零下10度,路况尚好但有地方结冰. I90高速公路路程较远,经过的Snoqualmie Pass海拔921米,气温零下5度,路况很好. 于是打定主意,

3. 关：要 to want; to need; shall; vital; important, demand; coerce | 关 to close; shut; concern; relationship; turn off; mountain pass | 头 head; the first; leading

noun

1. the location in a range of mountains of a geological formation that is lower than the surrounding peaks

e.g. we got through the pass before it started to snow

Synonym: passnotch